Automatic by-pass for hydraulic mechanisms



Aug. 14, 1934. R ERUNG 1,969,736

AUTOMATIC BY-PASS FOR HYDRAULIC MECHANISMS Filed March 8, 1933 3Sheets-Sheet 1 INVENTOR RALPH ERUNG. BY

ATTORNEY Aug. 14, 1934. ERUNG 1,969,736

AUTOMATIC BY-PASS FOR HYDRAULIC MECHANISMS Filed March 8, 1953 3Sheets-Sheet 2 0 K K S (NVENTOR RALPH ERuNG.

ATTORNEY Aug. 14, 1934.

R. ERLING AUTOMATIC BY-PASS FOR HYDRAULIC MECHANISMS Filed March 8, 19333 Sheets-Sheet 5 INVENTOR RALPH ERLING. BY

0. ATTORNEY Patented Aug. 14, 1934 PATENT OFFICE AUTOMATIC BY-PASS FORHYDRAULIC MECHANISMS Ralph Erling, Alexandria, Va.

Application March 8, 1933, Serial No. 660,071

12 Claims.

(Granted under the act of March 3, 1883, as

REISSUED amended April 30, 1928; 370 O. G. 757) This invention relatesto mechanism for controlling hydraulic power apparatus used for moving aships rudder to prevent injury thereto by the rudder yoke being movedagainst the hard over stops under power.

An object of this invention is to prevent the setting up of destructivestresses in the rudder mechanism when the rudder has reached the hardover position.

A further object is to prevent overloading of the steering gear motor byforcing the rudder against the hard over stops, which overloading wouldcause the motor circuit breakers to open and result in loss of steeringcontrol.

In the drawings:

Fig. 1 is a schematic assembly view of one form of my invention in whichare utilized four rams and cylinders with automatic by-pass control onthe cylinders in which one pair of rams operates;

Fig. 2 is in general similar to Fig. 1, but the by-pass connects onecylinder of each of two pairs of cylinders;

Fig. 3 shows my invention applied to a mechanism comprising but one pairof cylinders.

In Fig. 1 the rudder 4 is mounted on a rudder post 5 to which isconnected a crosshead 6, the hard over stops 7 being provided to preventmovement of the rudder beyond the maximum rudder angle. The powermechanism for operating the rudder comprises rams 8, 9, 10 and 11operable in cylinders 12, 13, 14 and 15, respectively. While the rams 8and 9 and rams 11 and 10 may constitute a single member, yet forpurposes of facility of description, they are designated as separatemembers connected together. Rams 8 and 9 are connected to one end ofcrosshead 6 by a link 16 and rams 10 and 11 are connected to the otherend of the crosshead by a link 17.

The continuously operating variable delivery pump 18, driven by motor19, supplies liquid under pressure to two of the cylinders and withdrawsliquid from the other two cylinders. As shown in Fig. 1, wherein thearrows indicate di rection of flow of the liquid and the consequentmovement of the rams, the yoke and the rudder, the rams 11 and 8 arebeing acted upon by liquid under pressure discharged from pump 18, whilethe liquid is being returned to the pump from cylinders 13 and 14.

Cylinders 12 and 13 are connected together by a pipe 24, at the ends ofwhich are disposed'valves 25 and 26 that are loaded by means of springs2'1. Each of these valves is adapted to be pressed against its seat bypositive pressure in the cylinder adjacent thereto but will be unseatedby liquid under pressure in pipe 24. Stems 28 and 29 are connected tovalves 25 and 26 respectively and extend through apertures 30 in a lug31 carried by rams 8 and 9, there being a head 32 secured to the outerend of each of said stems.

The operation of the device is as follows: The liquid under pressurepasses from pump 18 through pipes 20 and 21 to cylinders 15 and 12,respectively, moving the rams in the direction indicated by the arrowsand turning rudder 4 in the clockwise sense. Shortly before the rudderreaches hard over stop '7, the lug 31 contacts head 32 on valve stem 28and opens valve 25, thereby permitting the liquid under pressure to flowfrom cylinder 12 through pipe 24 to valve 26 which is unseated therebyand so permits the liquid to flow into cylinder 13, thus equalizing thepressures upon the rams 8 and 9. Also, since cylinder 14 is connected tocylinder 13 by pipes 22 and 23, the pressures in cylinders 14 and 15will be equalized. It is obvious that this equalization of pressures inall the cylinders will check the movement of the rams and stop therudder before it is forced against stops 7. To swing rudder 4 in theopposite direction to that indicated in Fig. 1, the direction ofoperation of pump 18 would be changed to discharge through pipes 22 and23 to cylinders 13 and 14 and to return the liquid from cylinders 12 and15 to the pump, in which case the lug 31 would open valve 26 to equalizethe pressures in the several cylinders.

If the rudder is swung in the direction indicated by the arrow in Fig. 1when the ship is going astern the liquid is forced into cylinders 12 and15 through pipes 21 and 20, respectively, but at relatively smallpressure since the rams are being moved in the direction of the arrowsby water pressure on the rudder and the liquid in cylinders 13 and 14 isunder greater pressure than is that in cylinders 12 and 15. As-the ramsmove, the lug 31 contacts the head 32 on stem 28 which unseats valve 25and permits the liquid to flow through pipe 24 to valve 26 which,however, is not unseated due to the pressure in cylinder 13 beinggreater than that in cylinder 12. The liquid in cylinders 13 and 14 actsas a cushion and permits the rudder to move slowly into contact withstops '7, which releases the pressure from the liquid in cylinders 13and 14 and permits the pump to build up pressures in cylinders 12 and 15sufliciently to open the valve 26. As the valve 25 is being held openthrough contact of lug 31 with the head 32 on stem 28, all the cylindersare connected to the pump and are subjected to equal positive pressureswhich hydraulically locks the steering gear and prevents furthermovement of the rudder.

The embodiment of my invention shown in Fig. 2 is very similar to thatin Fig. 1 except that the cylinders 12' and 14 are connected together bya pipe 24' instead of connecting the cylinders 12' and 13' and each pairof rams carries a lug 31' to actuate the valves 25' and 26'. Theoperation is generally similar to that of Fig. 1 ei cept that thepressure released from cylinder 12' is transm tted to the suctioncylinder 14' of the other pair of rams instead or to the suctioncylinder 13' or the same pair of rams. The parts in Fig. 2 which areunchanged in their operation as compared with those in Fig. 1 and aresimilar thereto are given the same reference characters as in Fig. 1.

In Fig. 3 the rudder 4 is connected by means 0! a crosshead 33 torams 34and 35in cylinders 36 and 3'7. These cylinders are connected together bya pipe 38 controlled by valves 39 and 40 which are adapted to be openedby contact of ing 41 with the heads 42 on valve stems 43. The liquidunder pressure is transmitted from pump 18 through pipes 44 and 45 tothe cylinders 36 and 3'7, respectiveLv. The operation of this form of myinvention is believed to be sumciently clear from the description ofFig. 1 since it is in all respects the same as Fig. 1 except that butone pair of cylinders is used instead of two pairs.

It will be understood that the above description and accompanyingdrawings comprehend only the general and preferred embodiment of myinvention and that various changes may be made therein within the scopeof the appended claims,

without sacrificing any of the advantages of this invention.

The invention described herein may be manufactured and used by or forthe Government of the United States of America for governmental purposeswithout the payment of any royalty thereon.

I claim:

1. In combination, a rudder post, a crosshead connected thereto, fourcylinders arranged in pairs, said pairs being parallel and the cylindersin each pair being aligned, rams connected in pairs and disposed to beoperable in said cylinders, means connecting said rams to the crosshead,a pump to supply liquid under pressure, means connecting said cylindersto the pump to apply pressure in one cylinder of each pair and suctionin the other cylinder of each pair, the connections being such that theforces exerted on said crosshead due to the said positive pressure areadditive, a pipe connecting one cylinder of one pair to the othercylinder of the same pair, a lug carried by the rams operating in thecylinders of the last mentioned pair, a valve adapted to close each endof said pipe and disposed to be moved to closed position by pressure inthe ach'acent cylinder, a loading spring acting on each valve, a stemconnected to each valve and passing through an aperture in said lug andmeans on each stem adapted to be contacted by said lug to unseat one ofsaid valves substantially at the end of movement of the ram in adirection away from such valve.

2. In combination, a rudder post, four cylinders arranged in pairs, saidpairs being parallel and the cylinders in each pair being aligned, ramsconnected in pairs and disposed to be operable in said cylinders, meansconnecting said rams to the post, a pump to supply liquid underpressure, means connecting said cylinders to the pump to apply pressurein one cylinder of each pair and suction in the other cylinder of eachpair, the connections being such. that the forces exerted on saidcrosshead due to said pressures are additive, a pipe connecting onecylinder of one pair to the other cylinder of the same pair, a lugcarried by the rams operating in the cylinders of the last mentionedpair, a valve adapted to close each end of said pipe and disposed to bemoved to closed position by pressure in the adjacent cylinder, a loadingspring acting on each valve, a stem connected to each valve and passedthrough an aperture in said lug and means on each stem adapted to becontacted by said lug to unseat the valve substantially at the end ofmovement of the ram in a direction away from the respective valve.

3. In combination, a rudder post, four cylinders arranged in pairs, saidpairs being parallel and the cylinders in each pair being aligned, ramsoperable in said cylinders, means connecting said rams to said post, apump to supply liquid under pressure, means connecting said cylinders tothe pump to apply pressure in one cylinder of each pair and suction inthe other cylinder of each pair, said connection being such that theforces exerted on said post are additive, a pipe connecting the pressurecylinder of one pair to the suction cylinder of the other pair, a valvedisposed to close each end of said pipe, a loading spring acting uponeach valve, an apertured lug carried by each pair of said rams, a stemconnected to each valve and extending through an aperture in theadjacent lug and a member on each of said stems adapted to be contactedby the respective lug to open the valve substantially at the end ofmovement of the rams away from the valve.

4. In combination, a rudder post, a pair of opposed aligned cylinders,connected rams operable in said cylinders, means simultaneously to applypressure to one cylinder and suction to the other cylinder, a pipeadapted to connect said cylinders directly, a valve disposed to closeeach end 01' said pipe and adapted to be seated by pressure in theadjacent cylinder, a loading spring acting upon each valve, an aperturedlug carried by said ram, a stem connected to each valve and extendingthrough an aperture in said lug, means on each stem to be contacted bysaid lug to unseat a valve substantially at the end 195 of movement ofthe ram away from such valve and means operatively connecting said ramsto said post.

5. In combination, a plurality of pairs 01. cylinders, the cylinders ineach pair being opposed and aligned, a ram operable in each cylinder,the rams in each pair of cylinders being connected, a pump connected toapply simultaneously pressure to one cylinder of each pair and suctionto the other cylinder of each pair, a pipe connecting one positivepressure cylinder to a suction cylinder, a valve disposed to close eachend of said pipe and means operable by a ram substantially at the limitof its movement away from a valve to open the valve adjacent saidpressure cylinder.

6. In combination, rudder post, a pair of cylinders, connected ramsoperable in said cylinders, means simultaneously to apply pressure toone cylinder and suction to the other, a pipe adapted to connect saidcylinders directly, a valve disposed to close each end oi said pipe andadapted to be seated by pressure in the adjacent cylinder, an aperturedlug carried by said ram, a stem connected to each valve and extendingthrough an aperture in said lug, means on each stem to be contacted bysaid lug to unseat the valve substantially at the end of movement awayfrom such valve and means operatively connecting said rams to said post.

7. In combination, a plurality of pairs of cylinders, a ram operable ineach cylinder, the rams in each pair of cylinders being connected, apump connected to apply simultaneously pressure to one cylinder of eachpair and suction to the other cylinder of each pair, a pipe connectingone positive pressure cylinder to a suction cylinder, a valve disposedto close each end of said pipe and means operable by said ramsubstantially at the end of its movement away from the valve to open thevalve adjacent a pressure cylinder.

8. In combination, a rudder post, a pair of cylinders, a ram operable ineach cylinder, means to apply simultaneously pressure to one cylinderand suction to the other, a pipe connecting said cylinders, a valvedisposed to close each end of said pipe adapted to be moved toward itsseat by pressure in the adjacent cylinder but to be unseated by pressurein said pipe, a stem connected to and extending from each valve, meansto act upon said stem to unseat the valve adjacent the pressure cylinderwhen the ram in the pressure cylinder is near the limit of its outwardmovement and means operably connecting said means to said post.

9. In a device of the class described, a plurality of pairs ofcylinders, a ram operable in each cylinder, the rams in each pair ofcylinders being connected, apump connected to apply pressure to onecylinder of each pair and suction to the other cylinder of each-pair, apipe connecting the cylinders of one pair, a valve disposed to closeeach end of said pipe and adapted to be moved against its seat bypressure in the adjacent cylinder but to be unseated by pressure in saidpipe and means actuatable to unseat the valve adjacent the cylinder inwhich the pressure is acting when the ram therein is near the limit ofits outward movement therefrom.

10. In a device of the class described, a pair of cylinders, a ramoperable in each cylinder, said rams being connected together, means toapply pressure to one cylinder and suction to the other cylinder, a pipeconnecting said cylinders, a valve disposed to close each end of saidpipe and adapted to be moved against its seat by pressure in the.

adjacent cylinder but to be unseated by pressure in said pipe and meansactuatable to unseat the valve adjacent the cylinder in which thepressure is acting when the ram therein is near the limit of its outwardmovement.

11. In a device of the class described, a rudder post, a plurality ofcylinders, a ram operable in each cylinder, means to apply pressure tocertain of said cylinders and suction to, the others thereof, meansconnecting all of said rams to said post in such manner that the forcesexerted thereon by all the rams subjected to pressure at any given timeare additive, means connecting each pressure cylinder with a suctioncylinder, said last mentioned means being adapted to transmit pressurebetween said cylinders, a valve disposed to close each end of said meansand adapted to be seated by pressure in the'cylinder adjacent theretoand means operable by movement of the ram in such adjacent cylinder awayfrom the respective valve to unseat such valve as such ram approachesthe limit of the said movement.

12. In a device of the class described, a movable member, a plurality ofcylinders, a ram operable in each cylinder, means to apply pressure tocertain of said cylinders and suction to the others thereof, meansconnecting all of said rams to said member in such manner that theforces exerted thereon by all the rams subjected to pressure at any timeare additive, means connecting each pressure cylinder with a suctioncylinder, said last mentioned means being adapted to transmit pressurebetween saidcylinders, a valve disposed to close each end of said meansand adapted to be seated by pressure in the cylinder adjacent theretoand means operable by movement of the ram in such adjacent cylinder awayfrom the respective valve to unseat such valve.

RALPH ERLING.

